This LNCS volume contains the best papers presented at the 9th Conference on 1 Arti?cial Evolution, EA 2009, held in Strasbourg (France). Previous EA events took place in Tours (2007, LNCS 4926), Lille (2005, LNCS 3871), Marseille (2003, LNCS 2936), Le Creusot (2001, LNCS 2310), Dunkerque (1999, LNCS 1829),Nimes (1997, LNCS 1363),Brest (1995,LNCS 1063) and Toulouse (1994, LNCS 1063). For this ninth edition, authors were invited to present their originalwork r- evantto arti?cialevolution,including,butnotlimitedto:evolutionarycompu- tion,evolutionaryoptimization,co-evolution,arti?ciallife,populationdynamics, theory, algorithmicsand modeling, implementations, application of evolutionary paradigmstotherealworld(industry,biosciences,…),otherbiologically-inspired paradigms (swarm, arti?cial ants, arti?cial immune systems, …), memetic al- rithms, multi-objective optimization, constraint handling, parallel algorithms, dynamic optimization, machine learning and hybridization with other soft c- puting techniques. Submitted papers were reviewed by at least four members of the Inter- tional ProgramCommittee, which selected 23 papers to be presented during the conference out of 43 submissions. However, only 17 papers were included in the present volume, resulting in a 39.5% acceptance rate. We would like to thank the members of the Program Committee for their conscientious work, the authors for their greatly appreciated contributions, but also the members of the Organizing Committee who, once more, managed to put together a really enjoyable conference in Strasbourg. Finally, ?nancial and material support coming from ENSPS, Universit'ede Strasbourg, CNRS, R’ egion Alsace and the EA association contributed to the success of the conference and helped to keep registration fees very low.